Q: From Transformers to Barney, Sesame Street to Dora the Explorer, what, more than anything, do children's shows aired on American television lack?

A: Filthy sexual innuendo.

An easy one, I know. But consider Rainbow, a kids' show that ran on British TV for 20 years, from 1972 to 1992. (There have been ill-advised revival attempts, but that's neither here nor there.) By day, this show helped tiny Britons with their English skills while making them laugh. Oh, the laughter! By night, however, as evidenced by the YouTube below, Rainbow was a low-grade nightcrawler, a disgrace, a syphilitic pock upon the national consciousness. Check this video out (and read the transcript):

Kind of makes you want to take a shower, doesn't it? Kind of fantastic, too -- the sort of thing you always hoped would pop up in kiddie shows when you were 13 and babysitting some snotty two-year-old on a Friday night for $6 an hour and all the pop in the fridge.

To answer the inevitable question: no, that segment never aired. It was produced as an in-house joke/Christmas present for the Thames TV staff in 1979. So resheathe your swords, moral highgrounders.

To answer the other inevitable question: no, I don't know why the word "rainbow" is such a popular one for titles of children's shows. That's a better question for LeVar Burton.

But something I do know? This is a truly entertaining music/comedy sketch from Thomas F. Wilson, better known as Biff Tannen: